The present invention generally relates to the field of vehicle restraining devices that prevent movement of a vehicle away from a desired location. More specifically, the present invention relates to powered wheel chocking devices.
Powered wheel chocking devices have been developed to allow a vehicle (e.g., a straight truck, a trailer with or without a tractor, etc.) to be secured at a desired location (e.g., a loading dock) so that loading, unloading or other operations can be performed without risk that the vehicle will unexpectedly move away. Such wheel chocking devices typically include a chock that can be selectively moved by a drive mechanism between a chocked position and an unchecked position. These devices are commonly provided with visual and audible signals that indicate when the chock is in the chocked position and when the chock is in a unchecked position.
One type of powered wheel chocking device has been designed by Michel Roux, and is disclosed in European Patent Publication No. 537,075. The Roux device includes a chock that is movable between an unchecked lowered position and chocked raised position. The Roux device is designed to maintain the chock in a lowered position until the chock has been moved longitudinally into contact with the vehicle wheel. After contact with the vehicle wheel, further movement of the drive mechanism causes the chock to pivot to the raised position to secure the vehicle wheel.
A similar device is disclosed in U.S. Pat. No. 5,375,965 to Springer et al. The Springer device also includes a chock that is movable between lowered and raised positions, and the chock is designed to be moved longitudinally into contact with the vehicle wheel while the chock is in the lowered position. After contact with the wheel, the drive mechanism will continue to drive a portion of the chock until the chock moves to the raised position.
In one aspect, the present invention provides a wheel chocking device having a wheel chock that can be raised from a retracted position to a raised position. In the retracted position, the wheel chock is substantially flat, thereby allowing a truck to be driven over the wheel chock. In the raised position, the wheel chock can be engaged with the wheel of a truck to prevent the truck from driving away from a loading dock.
The wheel chock is preferably movable from a distal position, spaced from the truck wheel, to a proximal position, in contact with a truck wheel. In one embodiment, such movement is provided by an electric motor operatively connected to a worm screw that drives one or more drive nuts. In another embodiment, such movement is provided by pneumatic cylinders that drive cables or chains associated with pneumatic pistons positioned within the cylinders.
The wheel chock can be designed so that it stays in the retracted position while the chock is being moved from the distal position to the proximal position. Upon contacting the truck wheel, the chock can raise to the raised position. Alternatively, the wheel chock can be designed such that, upon movement from the distal position, the wheel chock immediately raises to the raised position. For example, the wheel chock can be raised utilizing a tension spring positioned between the front and rear of the chock assembly. The raised chock can then be moved toward the truck wheel. If the chock should encounter an obstruction in its path hanging down from the under carriage of the truck, the chock will deflect downwardly around the obstruction. After the obstruction is avoided, the chock will again raise to its fully raised position.
In yet another embodiment, as the wheel chock is moved from the distal position, the chock raises from the retracted position to an intermediate position. This intermediate position is lower than the fully raised position and lower than obstructions commonly hanging down from trucks. The chock is then moved toward the vehicle wheel. Upon contact with the vehicle wheel, the chock will raise from the intermediate position to the fully raised position.
Each of the above-described wheel chock assemblies is preferably driven by a drive mechanism at least partially positioned within a cavity formed underneath the surface upon which the truck wheel is positioned. More specifically, the wheel chocking device preferably includes a base plate positioned on the driveway leading to the loading dock, rails extending upwardly from the base plate, and a cover plate positioned over the rails to thereby form one or more channels between the cover plate and the base plate. The drive mechanism (e.g., worm screws, cables or chains) can be positioned within this channel. In use, the truck is first driven onto the cover plate, and then the wheel chock slides over the cover plate until it engages the truck wheel.
The present application also discloses a wheel chocking device wherein the wheel chock can be inserted laterally from the side of the wheel. More specifically, in the resting position, the wheel chock is positioned out of alignment with the plane of the vehicle wheel. After the vehicle is positioned at the loading dock, a drive mechanism is actuated to move the wheel chock longitudinally toward the wheel. When a locator member contacts the wheel, the drive mechanism continues to drive, resulting in the wheel chock moving laterally in front of the wheel.